freeflyer

I am installing an Alpine W502R into an Audi A3 1.8 TFSI Sportback (2007).

The front speakers are driven from the amplifier in the Alpine HU and work fine. I am aware that the rear speakers are driven by the OEM amplifier and require line level signals.

So I have wired some RCA connectors to the line inputs in the OEM wiring...





...and connected them to the 'AUX-OUT' on the Alpine HU.





I have also connected the 'remote turn-on' (blue/white wire) from the Alpine HU to the amp remote in the OEM wiring.





I can tell that the rear amplifier is turning on, because if I touch the line inputs (with the 'AUX-OUT' disconnected from the Alpine HU) I can hear both the left and right rear speakers pick up noise and hum.

So either the 'AUX-OUT' on the Alpine HU is not working or the signal is not compatible with the rear amplifier.

I have enabled the 'AUX-OUT' on the Alpine HU menu and played around with lots of other settings. I have even tried using the 'AUX-IN' connectors on the Alpine HU in case they are incorrectly labelled. But I just cannot get the rear speakers to work.

I know you can buy a converter to convert the speaker out signal to a line out signal, but the Alpine HU already has l'AUX-OUT' RCA connectors so I had planned to use those instead.

freeflyer

OK so I think I've found the problem.

I tried connecting a different device (a camcorder) with line outs and it worked fine, so the issue was obviously the Alpine HU.

I've now found out that there is another lead for pre-amp front/rear/left/right & sub.




I dont know what the other lead with AUX-OUT is used for but its obviously not suitable for the amp.